Expanded clay concrete screed: device options

The adaptability and efficiency of expanded clay concrete screed make it a popular choice in construction. This kind of screed is ideal for a range of building applications because it creates a sturdy yet lightweight layer by mixing cement, water, and expanded clay aggregate. Its primary benefit is that it has good insulation qualities, which make it a great choice for both acoustic and thermal insulation.

The ability of expanded clay concrete screed to lower the overall weight of the structure is one of its main advantages. This makes it especially helpful for remodeling projects where there may not be much room for additional load-bearing capacity. Its strength is unaffected by its lightweight design, making it an excellent base for flooring and additional finishing layers.

Expanded clay concrete screed can be installed in a variety of methods, depending on the demands and specifications of the project. There are solutions for every situation, whether you want a bonded screed for increased stability or a floating screed for better insulation. These choices preserve the intrinsic advantages of expanded clay aggregate while providing flexibility in reaching the intended result.

Using expanded clay concrete screed in your construction project will improve the functionality and comfort of the building considerably. It is a workable solution for contemporary construction needs due to its simplicity of use and adaptability to different conditions. You can choose the device that best fits your project by being aware of the various options available to you and the applications that each one is designed for.

Device Option	Description
Traditional Screed	A basic mixture of expanded clay, sand, and cement, used for leveling floors.
Insulated Screed	Includes an additional layer of insulation material to improve thermal efficiency.
Lightweight Screed	Uses a higher ratio of expanded clay to reduce overall weight, suitable for upper floors.
Fast-Setting Screed	Formulated to dry quickly, allowing for faster completion of flooring projects.
Reinforced Screed	Incorporates metal or plastic mesh to increase strength and durability.

Features of expanded clay concrete

Expanded clay concrete is different from regular concrete mix in that it contains expanded clay, a loose substance made from fired clay, in place of crushed stone. It endows the solution with unique characteristics.

A few words about expanded clay

Expanded clay is a material that is good for the environment because it is made from natural raw materials. Its low weight, porous structure, high thermal and sound insulation qualities are all the result of a unique production technique.

In addition, unlike other insulating materials, it does not rot, corrode, or promote the growth of microorganisms. For these reasons, it can be utilized to build screeds beneath the ground.

The size and form of the fractions determine the material’s classification. The purposes of concrete screed containing varying fractions of expanded clay are distinct.

The material’s bulk density, expressed in kilograms per cubic meter, is contingent upon the grain size and, in the end, the expanded clay concrete screed’s weight. The expanded clay grade (which ranges from 150 to 800) reflects the bulk density.

Kindly take note. Given that its granules are entirely shielded by a dense, sintered shell, gravel has the lowest water absorption of any material.

Greater cost is associated with expanded clay than with crushed stone. However, the concrete mixture’s composition has many benefits as well. And not just within the blend. It is loose and lightweight, making it possible to level surfaces with significant height differences without placing undue strain on the ceilings.

Advantages and disadvantages of expanded clay concrete

The following are expanded clay concrete’s primary benefits:

• Relatively light weight;
• High sound and heat insulation characteristics;
• Durability and resistance to fire (unlike most other insulation materials).

Because the solution is lighter, expanding clay concrete for floor screeds is simpler to prepare and apply. However, because this material is quite brittle, expanded clay concrete floor screeds should only be used in small-load rooms.

For instance, applying a coating in a workshop that has heavy machinery is not appropriate. However, this is a great choice for garages, outbuildings, and public and residential buildings.

One of the material’s drawbacks is that, when poured, the solution becomes uneven because light granules float to the top. Consequently, it needs to be ground or another sand-concrete screed needs to be created.

Nevertheless, you can avoid labor-intensive extra work by using a technology for installing expanded clay concrete screeds. But it’s worth going into detail about this and other strategies.

Methods for installing expanded clay concrete screeds

Such a screed can be made primarily in two ways: semi-dry and wet. Let’s think about both.

Wet method

This expanded clay concrete screed pouring technique works better in spaces where thermal insulation is not as crucial. It can be completed on floors made of reinforced concrete as well as those prepared with crushed stone and sand on the ground.

The truth is that expanded clay has a high thermal conductivity coefficient and a low heat-saving capacity when it gets wet from absorbing water. However, since this method is the quickest and least labor-intensive, it is excellent if the goal is not to significantly insulate the floors.

The surface needs to be ready before applying expanded clay concrete screed.

• Clean the floors from old coverings and debris, seal cracks and joints.

• Protect wires and cables (if any) from damage by enclosing them in a corrugated pipe or cable ducts.

• Beat the fill level on the walls and place beacons on the floor, fixing them with plaster or alabaster. The distance between the beacons should be less than the length of the rule with which you will equalize the screed.

• Stick damper tape around the perimeter of the walls to compensate for temperature expansion and absorb vibration vibrations.

Suggestions. Wooden slats installed along the walls of an appropriate width can be used to replace the damper tape. The slats are removed and foam is poured into the void left by their removal once the expanded clay concrete floor screed has dried.

When everything is prepared, you can combine expanded clay with concrete to make screed. The following ratios are used to take the components: One part expanded clay, three parts sand, and one part cement.

Suggestions. It is preferable to use expanded clay with mixed fractions so that the spaces between the larger particles are filled in with smaller ones.

• The solution can be prepared both in a concrete mixer and in a suitable container. In the latter case, first the filler is poured into it and filled with water 2-3 cm above the granules.
• When it is absorbed, the sand-cement mixture is added to the expanded clay with constant stirring.

• The resulting solution is immediately laid out on the floor between the beacons and leveled, making the pouring surface 2-3 cm below the level of the beacons.

This is a crucial matter. The required amount of material needs to be prepared ahead of time because the expanded clay concrete screed must be poured over the entire area at once, without taking lengthy breaks in work.

• To give the screed strength, you can reinforce it with a metal mesh between the layers.

• As soon as the coating has set enough to be walked on, a standard sand-cement mortar is prepared and poured on top of the expanded clay concrete – the final floor screed is leveled with a rule along the beacons.

• To ensure that the solution sets evenly and does not crack, the surface is covered with polyethylene film to retain moisture, or sprayed with water several times a day.

Advice: There won’t be any cracks if you prepare the solution with plasticizing additives.

The temperature and humidity levels affect how long the screed takes to dry. As soon as it begins to slightly set and is able to support a person’s weight, the beacons must be removed. And mortar should be applied to the resulting voids.

A brief discussion of waterproofing beneath the screed. Since expanded clay granules in the wet method are shielded from moisture by a cement composition, it is not necessary to do so. Depending on the fraction sizes, the minimum thickness of the expanded clay concrete screed varies. However, it is not advised to make it any smaller than 4 cm.

Semi-dry method

A classic concrete solution is not practical if you need to raise the floor level to a great height or if you need to insulate and soundproof it. A thick layer won’t address the issue of thermal insulation at all; instead, it will place an enormous load on the floors.

Under the screed, you can place insulation, like expanded polystyrene. This is how things are usually done. However, a screed composed of sand concrete and expanded clay will be quicker and less expensive. Using dry insulation, the floor is leveled, and a concrete screed is created on top of it, following the beacons.

First, as was previously mentioned, preparatory work is completed. But they are joined by an additional stage. In the event that the expanded clay concrete screed device does not mandate base waterproofing, hygroscopic expanded clay must be shielded from excessive moisture in order to preserve its low thermal conductivity.

Waterproofing can be done however is most convenient:

Next, as per the plan, install the damper tape and beacons first.

Subsequently, the directives alter:

• Between the beacons, starting from the corner farthest from the entrance, dry expanded clay is poured. The more heterogeneous its fractions, the denser the backfill will be.
• The backfill is leveled and compacted, carefully filling all the corners and joints so that there are no voids. Its level should be below the level of the beacons.

• To prevent the expanded clay from "walking" under the concrete screed, a reinforcing mesh with a cell size of 10 × 10 cm is laid on it. It should be without defects – bulges and bent sharp edges protruding above the general level. Around the perimeter between the walls and the mesh there should be 3-4 cm of free space.

Once more, we go back to the method used to create the expanded clay concrete screed; the finishing leveling coating is applied using the same technology. A dry sand-cement mixture can be used in bags; just dilute it with water as directed on the package.

Alternately, mix your own solution by mixing one part M400 cement to three parts sand. Its consistency ought to be fairly thick.

When performing such work on your own, the desire to cut labor costs and save money frequently leads to technology violations. This may have unfavorable effects:

To help you avoid making these errors again, we have listed them below:

• Lack of reinforcement. In this case, the steel mesh serves not so much to prevent the formation of cracks, but to create a rigid barrier between the screed and the unstable underlying layer. It creates resistance to bending under local impact loads on the surface.

• Screed thickness too small. In living rooms it should be at least 40 mm to ensure the coating has the required strength. In rooms with high loads (hallway, kitchen, gym) it is increased even more.

• High water content in the solution, due to which it shrinks significantly when drying with the formation of cracks. The optimal ratio of water to sand-concrete mixture is considered to be 5-6 liters per 50 kg.

Concrete volume calculator

Screeds made of expanded clay concrete are a practical and effective way to level and insulate floors. Because of their lightweight design, they are perfect for both new construction and renovation projects and are easy to handle. By improving sound and thermal insulation, this kind of screed makes a home more cozy and energy-efficient.

When it comes to laying an expanded clay concrete screed, there are several choices. There are two options available: a wet method in which the expanded clay is combined with cement and water, or a dry method in which it is used as loose fill. Depending on the current floor structure and your unique needs, each method has advantages.

Expanded clay concrete screed has insulating qualities as well as offering a sturdy and stable foundation for various floor coverings. Regardless of whether you intend to install carpet, laminate, or tiles, this screed guarantees an even and smooth surface. It is a dependable option for both residential and commercial buildings because of its resistance to fire and moisture.

All things considered, choosing an expanded clay concrete screed is a useful and efficient method to raise the caliber of your flooring. It is a wise investment for any building project because of its insulation, simplicity of installation, and adaptability. You can customize the screed to best meet the needs of your project and get the best results by being aware of the various device options.

For both residential and commercial buildings, an expanded clay concrete screed is a great flooring option because of its insulating qualities and lightweight design. This kind of screed increases thermal insulation and soundproofing by combining expanded clay aggregate, cement, and water to create a long-lasting and energy-efficient layer. Expanded clay concrete screeds provide a range of installation options to suit a variety of project requirements, whether you’re looking to level floors, increase load-bearing capacity, or find a sustainable building material.

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